Chicago Harbors, including the boat ramps, are closed through April 7.
Here is the key paragraph from the online release:
Chicago Harbors Closure: Beginning March 21st, all docks, boat storage facilities, parking lots, launch ramps, and other harbor properties will be closed to the public through April 7 in accordance with Governor Pritzker’s stay-at-home order and the resulting Chicago Park District closures. We will keep you updated as this changes. Please note that the Chicago Harbors administration office will still be open, operating remotely.
Click here to read the extended posting.